Why You Can Drink Vinegar Yet not Sulfuric Acid

Why You Can Drink Vinegar Yet not Sulfuric Acid

Comparing Corrosivity of Different Acids

By Anne Marie Helmenstine, Ph.D.

Updated June 04, 2019

You can drink vinegar, but you can't drink diluted forms of other acids, such as battery acid. Here is the explanation for why it is safe to drink vinegar.

Why Drinking Vinegar Isn't Dangerous

Vinegar is a natural form of dilute (5%) acetic acid, CH3COOH, which is a weak acid. Battery acid is about 30% sulfuric acid, H2SO4. Sulfuric acid is a strong acid. Even if you diluted the battery acid so that it was 5% acid, like vinegar, you still would not want to drink it. Strong acids, such as battery acid, completely dissociate in water (or your body), so at the same dilution, a strong acid is more active than a weak acid.

However, the strength of an acid is not the main reason why you would not want to drink battery acid. Sulfuric acid or battery acid is much more corrosive than vinegar. Battery acid reacts strongly with the water in human tissue. Battery acid also tends to contain toxic impurities, such as lead.

It's safe to drink vinegar because the 5% acetic acid has a concentration of about 1M and a pH around 2.5. Your body contains buffering agents that prevent a weak acid from adversely affecting the acidity of your tissues. You can tolerate vinegar without any ill effects. This is not to say that drinking straight vinegar is good for you. The acid acts on the enamel of your teeth and drinking too much vinegar can make you sick.

People drink other diluted weak acids, too. Soft drinks usually contain citric acid, carbonic acid, and phosphoric acid. Carbonic acid forms whenever carbon dioxide bubbles through water.